Ball mill



July2, 1929. RBERNHARD 1,719,164

BALL MILL Filed April 30, 1928 5- Sheets-Sheet 1 I nuenl'or: Ric/landBernhard, ,y w M W y 2, 1929- V R. BERNHARD 1,719,164

BALL mm.

Filed April '30. 1928' s Sheets-Sheet 2 l nven Z'or:

July 2, 1929.

R. BERNHARD BALL MILL 5 Sheets-Sheet 3 Filed April 30, 1928 Inventor:

R ichand Bernhard y .19 29. R.BERNHAR'D 1,719,164

BALL mm.

Filed A pril so, 1928 5 Sheets-Sheet 4 z I 2 2 b N a 6 2 6% Q 4 Q 2 a- 4E fl v 2 V fi 1 b Inueni'or.

I I Jive/land Bernhard,

y 2, 1929- R. BERNHARD 1.719.164 BALL MILL Filed April 30, 1928 sSheets-Sheet 5 lnueni'on' I is Richard Bernhard,

Patented Jul 2, 1929.

UNITED STATES PATENT orrica.

RICHARD BERNHABD, OF ALLENTOWN, PENNSYLVANIA, ASSIGNOR TO TRAYLORENGINEERING & MFG. COMPANY, OF .ALLENTOWN, PENNSYLVANIA, A. CQBPOBA-BALL MILL.

Application filed April 30, 1928. Serial No. 274,013.

I My present invention relates to nnprove-.

. new or PENNSYLVANIA.

ments in ball mills of the multiple grinding compartment type in which;the material ground in one compartment is sulnected to a screeningaction as the mill rotates and the oversize rejected, while the linesare delivered into asucceeding con'ipartment for further grinding.

The invention relates more particularly to thediaphragm, grate, andscreen constructions and the way in which these are combined with themilldrum sect-ions and the manner in whichthe various parts are securedn place, all with a view to producing a null economical of productionand assembly, one in which the parts will all be securely held in place,and properly protected. resulting in a mill which is durable andetticient in use.

W'ith these and other objects in view. which will hereinafter appear,the invention Includes the novel features of const rnct ion hereinafterdescribed, the nature and scope of the invention being defined by theclaims appended hereto. 2 \Vhat I at present. consider the preferredembodiment of the invention is illustrated in the accompanying drawings.in which:

Fig. 1 is a central longitudinal section through the adjacentport-ionsof two null compartments embodying my invention.

Fi 2 is a transverse vertical section line 2-2 of Fig. l viewed aslooking toward the left. a

Fig. 3 is a similar section through the coarse grinding compartment online 3-3 of Fig. 1 and viewed looking toward the right.

Figs. 4 and 5 areenlarged developed fragmentary sectional views on lines44, and 5-5 respectively of Fig. 1.

Fig. 6 is a sectional view similar to Fig. 1 showing a modification.Figs. 7, 7" and 7" are detail views of wedge -1neans. h Figs. 8, 8 and 8are detail views of key means. and i Fig. 9 is a sectional view showingthe wedge and key means juxtaposed.

In these drawings I have illustrated'but two portions of ad ace-nt millcompartments,

but it will be understood that as the end portions of the mill form nopart. of the present invention illustration thereof is deemedunnecessary. It will also beapparent that the through the fine grindingcompartment on drical shell of one grinding compartment and 1 thecorresponding shell of the next sue ceeding compartment, which. in atwo-stage mill, would be provided with suitable heads formingcompartments A and A, closed except for the usual feed opening forcompartment A and discharge opening for compartment A, these feed anddischarge openings being usually arranged in the hollow trunnions of themill which, as they form no part of the present invention and are wellunderstood by those skilled in the art, are not shown herein. Theseshells, in the preferred embodiment shown, are made of different sizeswhereby the finer grinding compartment A is of less internal'diameterthan the coarser grinding compartment A. The connection between thesetwo shell members if formed by a ring or annular member 2 which has anannular flange 2 to which the shell 1 is riveted or otherwise securelyattached, and an oilsetannular flange 2" to whichthe shell 1 issimilarly secured. Preferably the shell 1 is secured to the externalperiphery of the flange 2* while the shell 1 is secured to the insidefaceof the. flange 2". This ring member 2 has an inwardly extendingannular web or diaphragm 2 which. together with the lining or facingplates and closure and clamping member for the central opening thereof(hereinafter described), constitutes an imperforate p'artitionseparating the two mill compartment-s.

Said web or diaphragm 2 has extending from the face turned towardscompartment- A and adjacent the central opening of the diaphragm. anannular flange 2 having at its free edge a rebate forming a support forthe inner ends of the grate bars 3 as indicated at d. The annular ringport-ion 2' has. adj acent its free edge. an annular inwardly extendingflange 2' having a thickened inner edge which 'is provided with anapproximately broad V-shaped groove e to receive and support the outerends of the grate bars.

, The grate bars are all duplicates of each other and eachcomprises atapered bar 3 their ends in engagement with the seats (I andrespectively, and when so placed will be self-sustaining by reasonof-their forming a complete ring 0 truncated cone shape.

For forcing of the bars into close contact with each other and lockingthem firmly in place during-the operation ofthe'mill, I pro- Wldfl'wedging and key ng means m the shape with the plates 6, such zincfilling being inofwedge members 4 which are placed in positionsimultaneously with the grate bars, and key members 5, which are driveninto placefrom the center of the mill and thereby crowd the gratemembers firmly together. These wedge and key members are shown in detailin Figs. 7 to 9 inclusive. 7

The key members 5 are preferably, of less thickness than the members 4and are guided in their insertion by the flanges 4- of said members 4.

For protecting the outer ends of the grate bars and the face of theflange 2 which would otherwise be exposed to the action of the: ballsand material in compartment A, I provide a plurality of segmental liningand wearing plates 6 (made in sections for convenience of insertionthrough the customary drum manholes) and which have thickened ends tooverlie the face of said flange 2 and provide annular shoulders adjacentto the ends of the grate bars. The plates 6 may be bolted or otherwisesecured in )osition and the spaces between their side edges and be tweentheir end edges and the flange 2, is filled with molten zinc, indicatedat 7, which not only aids in holding the liner plates in position butcloses up all gaps and prevents erosion. The outer edges of the 'ea rplates.

6 abut the usual shell liners 6, and the space between such shell linersand between the liners and the wear plates is likewise filled withmolten zinc.

The face of the diaphragm or partition member 2 which is towards thecompartment A is protected by segmental wear plates 8, the outer edgesof which lie between the liner plates 9. and the diaphragm. 2, and theoint-s of which are filled with molten zinc in a manner similar to thatdescribed in connection dicated at 7.

The plates 8 at their inner edges are held by a disc member 10 having arebated'edg& to receivethe corresponding rebated inner edges of theplates 8. .Said disc member 10 has a central recess to receive a lockingbolt 11, the head 11 of which is seated in a' rebate o r{ ;;counter sinkin the member and held against rotation by' key means, such as indiratedat 11". The bolt has a fine thread which cooperates with thecorresponding threads'of a clamping nut 12 which is seated in and bearsagainst the recessed face of a holding and protecting plate 13, thewhich abuts the inner en s of the grate bars and edging and keying meanstherefor.

By sledging the nut onto the bolt by means of the ribs 12" the parts maybe drawn very firmly together and securely held in place.

The space betweenthe grate bars 3 and the Pttl'tltlOIlfOl'lllS anannular compartment B to receive the material which is ground inchameripheral edge of her A to such size, as to pass the openings Vbetween the grate bars. This material is sub;

jccted to a further sepa- 'ation by the means which will now bedescribed.

The flange member 2" is provided at its edge with an annular outwardlyextending flange 2 integral therewith and disposed in a planeperpendicular to the axis of the mill, and the shell 1 carries fastthereon a similar flange member 14,'these flanges having theirperipheral edges .oquidist'ant from the'mill axis and preferablyrebatedas shown. The

' edge faces of these flanges serve to support an annular screen 15,which is secured to the flanges by means such as bolts 20. Thus 1sformed between the screen and drum an annula-r chamber C whichcommunicates with the chamber-B by means of the ports 16, 17 .and 18arranged in staggered relation to each other, whereby, as the millrotates, the material in chamber B will be delivered at various pointsinto chamber C. Over-lying the screen 15 is an annular closure member 19formed by sheet. metal segments having their abutting ends provided withangle iron reinforcements 19 Fig. 2 bolted together as indicated at 19".These sections are supported in ,spaccd relation to the screen 15 byZ-shaped irons 19 having their base flanges secured by the bolts 20 andtheir outer flanges rebated to form seats for .the closure members 19.

These members 19* and 19 form another annular chamber D outside thescreen 15 which receives the material which is fine enough topassthrongh said screen. The material thus collected in chamber D, inthe rotation of the mill, encounters the inclined deflectors 21 rigidlycarried within the chamber D by which it is deflected towards the end ofthe said chamber D which overlies the adjacent end of the line grindingcompartment A. As the mill rotates. said deflected fines encounter theeccentric deflector 22 by which they are deflected through screenopenings 15 into compartments It having eccen tric walls 22 forming acontinuation of deflectors 22, which deflect the fine material throughpassages 23 in the shell and lining into the fine grinding compartmentA'..

The rejects in compartment C as the mill rotates, encounter thedeflectors 24 (which are inclined rcversely to the deflectors 21) andare thereby deflected t0wards' the side of chamber C overlying thecompartment A,

whence they'are delivered inte -pockets G formed at the sides of thecompartment G and find their way through ports or passages.

r and partition arrangement may be used to partition 2 is formedintegral therewith and has a central opening to which is applieadvantage in a mill in which the-rejects are merely retained in thecoarse grinding compart-ment by the grate and all the material passingthrough the grate enters directly-into the fine grinding compartment.Such an embodiment is shown in Fig. 6 in which A designates the coarsegrinding compartment and A the tine grinding compartment.

In this form the annular member 2" is preferably formed of approximatelywedge shape in cross section and hollow for lightness and carries at itsthicker end a rebate forming a seat for the grate bar ends. The

a circular member which has a rebated edge which engages the inner endsof the weary plates 8 and clamps them to the web 2.

Said member 1O has a cross bridge 10 which has an opening for thepassage of the bolt 11%.

The member for supporting the inner ends of the grate bars is in thiscase formed as a separate member 2 of dished form seated against thecross bridge and both the cross bridge and member 2 have ahned openingsthrough which the bolt 11 passes as also it 'ing the ends of thegratedoes through an opemng formed in the recessed central part of theholding and protecting plate 13", the parts being firmly clampedtogether by the nut 12".

.The outer ends 01. the grate bars are protected by wear plates 6similar to the wear plates 6 heretofore described.

Having thus described my invention, what I claim is:

1. A multiple compartment ball mill ineluding a pair of adjacentgrinding compartments, an annular member having a web forming apartition separating said compartments and prov1ded with a centralopening,

from said web and grooved to provide a, seat, grate bars assembled inthe form of a truncated cone and having their outer ends supported bysaid seat, and means supported by said web for'holding the inner ends ofthe grate bars. p

2; A .ball mill according to claim 1 in which wear plates are pnpvidedfor protectars.

3. A ball mill according to claim 1 in which a circular member issupported by the par;

- I tition web, the inner ends-oi the gratebars are seated in an annulargroove in the edge of the circular member and held therein by aclamping" plate having means fqr' holding it clamping position.

lar laterally extending 4. A ball mill having a partition dividing itinto two compartments, said partition hav-' ing a central opening,annular grate bar seats in one oi said com )artments arranged inparallel planes, grate ars having their ends supported by said seats, aholding and protecting plate engaging the inner ends of the grate ars, acircular member having a rebated edge bars, and having a recess in thecentral part.

thereof, a circular member havinga rebated d edge engaging the centralopening in the partition, a bolt having its head countersunk in saidcircular member and projecting through the same and through the holdingmember, and a nut on said bolt seated in the recess in said holdingmember.

6. A ball mill having inner and outer annular flange members havingseats for grate bar ends, saidseats being disposed in spaced apartparallel planes, radially arranged grate bars supported by said seats,wedge bars interposed at intervals between said bars, said wedge barshaving their narrowest end portions towards the axis of the mill, andkey means inserted between said wedge bars and the adjacent grate barsfrom the centenof the mill.

7. A multiple compartment ball mill including a. pair of cylinders ofdifferent diameter and partition and grate supporting means comprisingan annular member having I stepped concen ric flanges to which theadjacent ends of the shells are respectively rigidly seeured.

8. A multiple compartment ball mill including a pair of juxtaposedcylinders, and an annular member having flanges to which d the adjacentends of said cylinders are secured, said annular memberhaving anintegrally extending partition member, an annular laterally extendinggrate supporting flange carried by said partition member, an inwardlyextendm flange carried by said annular member a jacent the edge thereofwhich overlies the coarse grinding compartment and radially arran edgrate bars having t eir ends supported y said flange.

9. A multiple compartment ball mill including a pair of juxtaposedcylinders, and an annular member having flanges towhich the adjacentends. of said cylinders are secured, said annular member having anintegrally extending partition member, an annugrate supporting flangecarried by said partition member, an inwardly extending flange carriedby said allnular member adjacent the edge thereof which overlies thecoarse rinding compartment, said laterally extendingflange having itsedge located nearer the partition than the edge'of said inwardlyextending flange,

the edges of said flan es being rovided with grooves, and a plurality ofradially arranged grate bars having their ends seated in said groovesand forming a grate of truncated conical form.

10. A multiple compartment ball mill including a pair of juxtaposedcylinders, an annular men'iber'having flanges to which the adjacent endsof said cylinders are secured, said annular member having an inwardlextending partition member provided with a central opening, radiallyarranged grate members supported from said-annular member and partition1n spaced relation to the latter,'a .plurality of segmental wear platesoverlying said partition, and a closing plate for the central openingoverlying the inner edges of the wearplates, wit-h means for holdingsaid closing plate in position.

11. A multiplecompartment ball. mill in cluding apair of uxtaposedcylinders, an annular member having flanges to which the adjacent endsof said cylinders are secured, a transverse partition member carried bysaid annular member, having a central opening, an annular laterallyextending flange carried by'said partition member adjacent said openingand having a rebated edge, radially arranged grate bars having theirinner ends supported by saidrebated edge, means carriedby said annularmember for supporting the outer ends of the grate bars, segmental wearplates covering the face of the partition member, a closure disc for thecentral opening having an edge for engaging and holding the inner edgesof the segmental wear plates, at second disc member having its edgeengaging portions of the inner ends of the grate bars, and means fordrawing said discs together and locking them in position.

12.' ,A multiple compartment ball mill including a pair of juxtaposedcylinders, an annularauember having flanges to which the adjacent endsof said cylinders are secured, a transverse partition member carried bysaid annular member having a central opening, an annular laterallyextending flange carried by said partition member adjacent said openingand having a rebated edge, radially arranged grate bars having theirinner ends supported by said rebated edge, means carried by said annularmember for supportin the outer ends of the grate bars, segmenta wearplates covering the face of the partition member, a closure disc for thecentral-opening having an edge for engaging and holding the inner edgesofthe se mental wear plates, 0. second disc member having its edgeengaginw portions of the inner ends of the grate ars, said second discmember having a deflected central portion, a nut seated in the recessformed by such deflection, and a bolt passing through openings in thefirst and second discs and engaging said nuts. 13. A multiplecompartment ball mill including a pair of juxtaposed cylinders, anannular member having flanges to which the ends of said cylinders aresecured, a partition member having a laterally projecting annular flangeadjacent the axis of the mill, radially arranged grate bars having theirinner ends supported by said-flange, one of said cylinder -arryingflanges having, an inwardly extending flange having an edge adapted tosupport the outer ends of said grate bars, and segmental wear platescovering the face of said inwardly extending flange and protect ingtheouter ends of the grate bars. a

'14. In a ball mill of the'elass described having partition members,inner and outer flanges carried by said members having rebated edges toform grate end receiving grooves, radially disposed grate bars supportedby said edges, locking wedges inter posed between certain of said gratebars and driven from the center outwardly to crowd said bars together,and locking and protect ing means overlying the inner edges of the barsand wedges.

15. In a'ball mill of the class described having partition members,inner and outer flanges carried by said members, said outer flangehaving an internal grooved edge to recci re and support grate bar ends,said inner flange having its edge disposed in a plane offset from theplane of the outer flange, and said edge having an annular shoulder,radially arranged grate bars having their outer ends seated in thegroove of the outer flange and their inner ends supported by saidshoulder, said inner ends being of greater depth than said shoulder, andwedging means driven from the center outwardly past said shoulder andbetween certain of the grate bars for crowding them together.

16. In a ball mill, a rotatable drum having a transverse screenpartition forming coarse and fine grinding compartments, a grate spacedfrom said partition and providing'a collecting chamber for fines fromthe coarse grinding compartmel'lt, a chamber concentric to and rotatablewith the drum having an annular screen partition separating the chamberinto two concentric compartments, a duct placing one end of the innercompartment in communication with the coarse grinding compartments;opposite end of the outer of said concentric chambers in communicationwith the fine grinding compartment, said drum having ports leading fromthe collecting chamber centric compartment, and reversely inclined ductplacing the to the intermediate portion of the inner con-.deflectorsarranged in said inner and outer concentric(.Oll'lPfil'tlllEIltS.

17. Apparatus according to claim 16, in which the ports leadlng from thecollecting chamber are arranged in three rows and in staggered relation,the ports of the outer rows being inclined in opposite directions.

18. Apparatus according to claim 16 in which the inner commitment isformed by cirelnnferential flanges carried by the. drum to the outeredges of which flanges the an nular screen is secured, and the outerconcentric compartment is formed by an annular trough-shaped memberhaving its edges secured to the edges of said flanges.

19. In a multiple compartment ball mill,

.the combination with two drum sections of dm'erent size, of an integralreducer and connecting member having flanges to which the adjacent endsof said drum sections are secured, and a partition memner integral withsaidcmmecting member.

.In testimony whereof, I aifix my signature.-

RICHARD BERN HARD.

